As I understand you have RadGridView together with RadDataPager and you would like to navigate to a specific page and set the SelectedItem there. Is this correct?
Then, when you refresh the ItemsSource, RadGridView default to the first page and the selection is lost. Of this is the issue, then this would be an expected behavior.
When using the data pager the GridView shows only one page with the loaded data.It is actually not aware that there are other items to be loaded. Therefore, the SelectedItem cannot be persisted as it is currently not available into the grid.
You will have to select the same page and then select the item back.
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